<template>
  <view>
    <my-search @click="gotoSearch"></my-search>
    <view class="scroll-view-container">
      <!-- 左侧的滚动视图区域 -->
      <scroll-view class="left-scroll-view" scroll-y :style="{height: wh + 'px'}">
        <block v-for="(item, i) in cateList" :key="i">
          <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChange(i, item)">{{item.cat_name}}</view>
        </block>
      </scroll-view>
      <!-- 右侧的滚动视图区域 -->
      <scroll-view class="right-scroll-view" scroll-y :style="{height: wh + 'px'}" :scroll-top="scrollTop">
        <view class="cate-level2" v-for="(item2, i2) in cateLevel2" :key="i2">
          <view class="cate-level2-title">
            / {{item2.cat_name}} /
          </view>
          <view class="cate-level3-img-box">
            <view class="cate-level3-img-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <image :src="item3.cat_icon"></image>
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    mixins: [badgeMix],
    data() {
      return {
        cateList: [],
        // 当前设备可用的高度
        wh: 0,
        // 当前激活项
        active: 0,
        cateLevel2: [],
        scrollTop: 0
      };
    },
    onLoad() {
      const sysInfo = uni.getSystemInfoSync()
      this.wh = sysInfo.windowHeight - 50
      // console.log(sysInfo)
      this.getCateList()
    },
    methods: {
      async getCateList() {
        const {
          data: res
        } = await uni.$http.get('/api/public/v1/categories')
        if (res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        this.cateLevel2 = res.message[0].children
      },
      activeChange(i) {
        this.active = i
        this.cateLevel2 = this.cateList[i].children
        // scroll-top属性不能赋相同值
        // 滚动条回到顶部可以有1像素的偏差去让他来回切换
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      // 点击三级分类跳转到商品列表
      gotoGoodsList(item3) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
        })
      },
      gotoSearch() {
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    .left-scroll-view {
      width: 120px;

      .left-scroll-view-item {
        text-align: center;
        background-color: #F7F7F7;
        line-height: 60px;
        font-size: 12px;

        &.active {
          background-color: #FFFFFF;
          position: relative;

          &::before {
            content: '';
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }

    .right-scroll-view {
      .cate-level2 {
        .cate-level2-title {
          padding: 15px 0;
          font-size: 12px;
          font-weight: bold;
          text-align: center;
        }

        .cate-level3-img-box {
          display: flex;
          flex-wrap: wrap;

          .cate-level3-img-item {
            width: 33.33%;
            margin-bottom: 10px;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            image {
              width: 60px;
              height: 60px;
            }

            text {
              font-size: 12px;
            }
          }
        }
      }
    }
  }
</style>
